Chess in a Few Bytes
Linux has a good range of extremely strong chess engines such as Stockfish, Critter, Togo II, Crafty, GNU Chess, and Komodo. The chess engines featured in this article offer no match to a good chess engine, but they show how much can be achieved with a minuscule codebase.

GTK+ is a multi-platform toolkit for creating graphical user interfaces. Offering a complete set of widgets, GTK+ is suitable for projects ranging from small one-off projects to complete application suites. GTK+ is based on three libraries: GLib is the low-level core library that forms the basis of GTK+ and GNOME, Pango is a library for layout and rendering of text, with an emphasis on internationalization, and the ATK library provides a set of interfaces for accessibility. hot

(commercial) PDK provides tools for building self-contained, easily deployable executables for Windows, Mac OS X, Linux, Solaris, AIX and HP-UX. The comprehensive feature set includes a graphical debugger and code coverage and hotspot analyzer, as well as tools for building sophisticated Perl-based filters and easily converting useful VBScript code to Perl.

The Tcl Dev Kit (TDK) provides essential tools for Tcl programmers, making it
easy to create, build and deploy applications. Rapidly deploy applications in
multiple formats to a broad range of platforms, while protecting your code with
the pre-compiler. User interfaces make options clear and visible, helping you
get the most out of the tools.

a C++ XML parser toolkit that has a full SAX2 implementation (the Simple API for XML), including the optional interfaces and helper classes. It also implements the W3C Document Object Model Level 2.0 Core

a high-performance, open-source C-language library for parsing and generating XML and BXML (below) formats with a straightforward API. Initial testing indicates that it is 3 or more times as fast as other popular libraries such as expat and libxml2

DEPS (formerly known as graph-includes) is a set of tools and libraries which allows users to extract dependency information from arbitrary material (e.g. program source files), apply various transformations to this graph, and draw it. It is typically used as helper tool for a refactoring effort, to create a graph of dependencies between groups of source files.

DIVERSE is a cross-platform, open source, API for developing virtual reality applications that can run almost anywhere. DIVERSE currently runs on Linux, IRIX. Support for Windows XP and Mac OS X is under development. The goal of DIVERSE is to enable developers to quickly build applications that will run on the desktop as well as various immersive systems.

The Emerging Technologies Toolkit (ETTK) is a collection of technologies from IBM's software development and research labs that have special relevance to IBM?s emerging software strategy. Includes: Compound XML Document Editor: A standards-based, model-driven editor for mixed-namespace XML documents, XML Forms Generator: Model-driven Eclipse tooling for the generation of forms that adhere to the XForms 1.0 standard, from an XML instance document or a Web Services Description Language (WSDL) document, XML Enhancements for Java: A set of language extensions that facilitate XML processing in Java, and IBM Web Services Navigator: An Eclipse/RAD plug-in for interactive visualization of Web service transactions.

a C++ based Toolkit for developing Graphical User Interfaces easily and effectively. It offers a wide, and growing, collection of Controls, and provides state of the art facilities such as drag and drop, selection, as well as OpenGL widgets for 3D graphical manipulation

intended to be a 100% plug-compatible clone, and is released under the Xfree license. The GLUT (OpenGL Utility Toolkit) is a widely used library for doing window control, keyboard, and mouse input, and other basic functions for OpenGL programs

an open source software toolkit used for building grids. It is being developed by the Globus Alliance and many others all over the world. A growing number of projects and companies are using the Globus Toolkit to unlock the potential of grids for their cause

guile spread is a guile module that conveniently wraps the Spread C libraries provided with the Spread 3.15.2 distribution. Spread is a local/wide area group communication toolkit that runs on most modern operating systems. It allows convenient mechanisms for reliable multicasting information between applications as well as providing many more complicated assurances.

Hidden Markov Model Toolkit: a portable toolkit for building and manipulating hidden Markov models. HTK is primarily used for speech recognition research although it has been used for numerous other applications including research into speech synthesis, character recognition and DNA sequencing

(commercial) Hunny Mail++ is a cross-platform C++ library that provides classes for SMTP, POP3, IMAP4, and NNTP clients. This mature toolkit, which has been in active development since 1997, offers many features, including support for TLS (SSL) and the most popular SASL authentication mechanisms, IMAP extensions, and NNTP extensions. The toolkit comes with well-written documentation and numerous example programs, making it easy to use.

(commercial) a toolkit for communicating via SOAP. It uses SCL for service descriptions and is able to generate completely self-contained client stubs from such a description. With an SCL description IdooXoap is even able to (de)serialize any linked graph

a toolkit for GUI-based real time audio applications. Jezabel provides: a plugin interface for configurable audio processing elements with real-time control, an API for patching together plugins and running them in real time, and base classes for creating graphical user interfaces that control the operation of the audio plugins in real time, based on Qt

Libvirt is a C toolkit to interract with the virtualization capabilities of recent versions of Linux (and other OSes). It is free software available under the GNU Lesser General Public License. Virtualization of the Linux Operating System means the ability to run multiple instances of Operating Systems concurently on a single hardware system where the basic resources are driven by a Linux instance. The library aim at providing long term stable C API initially for the Xen paravirtualization but should be able to integrate other virtualization mechanisms if needed.

a cross platform, multi-threaded, royalty free C++ library and set of command tools for software developers. The MaxiWeb library implements a complete web server that can take the place of a general purpose web server such as Netscape Server, Apache, and Microsoft IIS

UWG is a lightweight gadget/windowing toolkit for C and X11. Interfaces are described using XML and are turned into C code using the ubuildinit utility. Currently, only a small percentage of the planned gadgets are implemented.

nb++ is a nuts-and-bolts C++ toolkit. It includes classes for basic operating-system features such as sockets, threads and regular expressions, along with threading strategies, a framework for writing daemons, and tools for reference counting and event dispatching.

a fast, and very easy-to-use GUI toolkit for Unix/Linux systems running X11. It is very flexible and is designed so that you can easily and quickly create a GUI for your application that looks the way you want it to without the long complex code

OpenNebula is a toolkit to easily build any type of cloud: private, public, and hybrid. OpenNebula has been designed to be integrated with any networking and storage solution and so to fit into any existing data center.

OpenTK is a cross-platform game development library for .Net/Mono. OpenTK provides intuitive low and high-level wrappers to OpenGL and OpenAL, window and context management, virtual controllers, a Math module and more.

a free cross-platform runtime for VRML available under the GNU Lesser General Public License. The basic OpenVRML distribution includes libraries you can use to add VRML support to an application, and "Lookat", a simple stand-alone VRML browser

Peers is a distributed programming toolkit designed for building peer-to-peer systems. The toolkit is a hybrid language project which offers low level primitives for managing concurrency and communication. Using these primitives, complex P2P protocols and complete systems can be designed and implemented in Python, while maintaining high performance for critical operations.

Portable, Extensible Toolkit for Scientific Computation is a suite of data structures and routines for the scalable (parallel) solution of scientific applications modeled by partial differential equations. It employs the MPI standard for all message-passing communication.

an object oriented windowing toolkit written in C++. It's meant to become an alternative to toolkits like Qt. SMOOTH provides classes for windowing, session management, object distribution and multithreading

Spread is a toolkit and daemon that provide multicast and group communications support to applications across local and wide area networks. Spread is designed to make it easy to write groupware, networked multimedia, reliable server, and collaborative work applications.

a set of open source audio signal processing and algorithmic synthesis classes written in C++. STK was designed to facilitate rapid development of music synthesis and audio processing software, with an emphasis on cross-platform functionality, realtime control, ease of use, and educational example code

he Template Numerical Toolkit (TNT) is a collection of interfaces and reference implementations of numerical objects useful for scientific computing in C++. The toolkit defines interfaces for basic data structures, such as multidimensional arrays and sparse matrices, commonly used in numerical applications. The goal of this package is to provide reusable software components that address many of the portability and maintennace problems with C++ codes.

The Parser Toolkit is a C++ STL-based parser toolkit that allows the specification of EBNF-like grammars (using operator overloading) and the conversion of arbitrary input (text, tokens or other) to user-defined structures through events attached to grammatic rules.

a modern secure, robust, multithreaded, exception aware, internationalisable, portable GUI toolkit library designed for mission-critical work in C++ and Python forked from the FOX library. It replicates the Qt API in many places and has been designed primarily for Tn, the port of Tornado to FOX

Visualization Toolkit is an open source, freely available software system for 3D computer graphics, image processing, and visualization. VTK includes a textbook published by Prentice-Hall ( The Visualization Toolkit, An Object-Oriented Approach To 3D Graphics, 2nd edition" ISBN 0-13-954694-4 ), a C++ class library, and several interpreted interface layers including Tcl/Tk, Java, and Python.

a portable LGPL free C++ toolkit for loading, displaying and processing X3D models. The library comes with simple applications and many examples that enable the visualization and the edition of X3D models.